In recent years, there have been proposed image forming apparatuses in which, by using a recording medium with RFID composed of a recording medium, such as various sheets, having incorporated therein an RFID (Radio Frequency Identification) tag, a printing on the recording medium can be performed and at the same time various information can be written in the RFID tag attached to the recording medium. For example, Patent Document 1 discloses an image forming apparatus in which a label printing on a label sheet with RFID having incorporated therein an RFID tag can be performed and at the same time information can be written in the RFID tag.
Meanwhile, there has also been proposed a method of attaching an RFID tag onto a picture and thereby writing information associated with the picture in the RFID tag. For example, Patent Document 2 discloses a method of performing a picture printing on a recording medium with RFID tag by a digital still camera having incorporated therein a printer.
However, when an RFID tag is incorporated into such product label and picture recording material, the following problems arise. For example, there is a risk in that the tag information is read by a third party without the owner of the printed material having incorporated therein an RFID tag knowing, thus invading the privacy of the owner. Also, when a printed material having incorporated therein an RFID tag is discarded, the information remains in the discarded RFID tag, causing a risk of leakage of information.
Meanwhile, as a countermeasure against leakage of information, methods for invalidating RFID tag have been proposed. In Patent Document 3, there has been proposed a voltage generation method for generating a voltage for breaking or disable a contactless card circuitry. According to the method, an IC tag on a contactless card is physically broken by an applied voltage. In Non-patent Document 1, the Auto-ID Center proposes the RFID tag specification in which the invalidation command is installed in an RFID tag, whereby when a product with RFID tag is purchased, the RFID tag is invalidated in the shop or the like. According to this technique, a specific apparatus (a dedicated apparatus) is used to transmit the Kill command to thereby invalidate the RFID tag.
[Patent Document 1] Japanese Patent Laid-Open No. 2003-140548
[Patent Document 2] Japanese Patent Laid-Open No. 2004-72146
[Patent Document 3] Japanese Patent Laid-Open No. 6-325223
[Non-patent Document 1] 14.4.8 Kill (binary ‘01 111111 1’) “Draft protocol specification for a 900 MHz Class O Radio Frequency Identification Tag” 23 Feb. 2003 (Auto-ID Center) (http://www.epcglobalinc.org/standards_technology/Secur e/v1.0/UHF-class0.pdf)
However, it is difficult for a general user to judge whether or not an RFID tag is attached to the recording medium. Thus, when the printed material or the product label is broken, it is not possible to judge whether or not it is necessary to invalidate it.
According to the conventional technique described above, in order to invalidate the RFID tag, a dedicated apparatus used to invalidate it must be provided. Thus it is not possible for a general user having the printed material or product with RFID tag to easily invalidate the RFID tag at home.
According to the technique in which the visual appearance of RFID tag does not vary, such as the technique of transmitting the Kill command and thereby invalidating RFID tag, it is difficult to confirm whether or not the RFID tag has been surely invalidated, thus causing the user to feel uneasy.
It is also difficult to judge from the visual appearance of the printed material with RFID tag whether or not information has already been written.